I recently put my 5 girls out into their run and coop for good. They are about a month old. The run is 8x 12 and is covered with grass. After about 4 days being in the run the ground is getting a bit "used" and getting covered with poop. After the grass disappears from wear and tear I'll probably cover it with sand.... but until then.... any suggestions how to "freshen" it up a bit.... keeping in mind the grass is still covering the ground of the run and about 4 inches high (although getting tramped down a bit). Thanks for the suggestions.